Printing apparatus and image transfer means



United States Patent Inventor David B. Spaulding Carllsle, Massachusetts Appl. No. 724,085 Filed April 25, 1968 Patented Nov. 17, 1970 Assignee By mesne assignments to International Telephone and Telegraph Corporation, Nutley, Newdersey a corporation of Delaware PRINTING APPARATUS AND IMAGE TRANSFER MEANS 5 Claims, 5 Drawing Figs.

U.S. C1 l01/ESD 197/1 Int. Cl B41f 17/00 Field of Search 101/1; 197/1 P01. 55 GENERATOR Primary ExaminerEdgar S. Burr Att0rneys-C. Cornell Remsen, Jr., Walter .1. Baum, Percy P.

Lantzy, Philip M, Bolton, Isidore Togut and Charles L. Johnson, Jr.

ABSTRACT: A printing apparatus is provided having means for transferring an image on a transfer band to a record sheet, wherein means are included for accelerating said band towards said record sheet and means on said band cooperate to cause rapid deceleration of said band and transfer of said image onto said sheet.

Patented Nov. 17, 1970 INVENTOR DAV/D 8.5PAULD/NC ATTORNEY I/I/I/I/I/I v v x Q 8 PRINTING APPARATUS AND IMAGE TRANSFER MEANS CROSS REFERENCE TO RELATED APPLICATIONS This application is related to the following previously filled disclosures: D.B. Spaulding-l Ser. No. 677,594,filed Oct. 24, 1967, now US. Pat. No. 3,477,368; D.B. Spaulding-Z, Ser. No. 692,816, filed Feb. 22, 1967, now US. Pat. No. 3,509,816; D.B. Spaulding-3, Ser. No. 699,714, filed Jan. 22, 1968, now abandoned; D.B. Spaulding-4, Ser. No. 696,276, filed Jan. 8, 1968, now abandoned; and D.B. Spaultling-5,Ser. No. 720,277,filed Apr. 10,1968.

BACKGROUND OF THE INVENTION In general this invention relates to a transfer band printing arrangement, and more particularly to printing apparatus utilizing inertial and surface bond forces as means for transfer ofan image from the band to a record sheet.

The prior art, as indicated in the above-identified crossreferences, involves a continuous moving transfer band which is utilized to accept a character image from a character forming station and to carry the image to a point adjacent a desired printout location. These disclosures dealt with the use of magnetic and electrostatic forces to cause the transfer at the printout location from the moving band to the record sheet. This invention, however, develops this concept further as it provides another method of removing the image from the band and placing it intact onto the record sheet. The means involve inertial, capillary and surface bonding techniques to cause transfer of the character image from the band onto the record sheet.

SUMM ARY OF THE INVENTION It is therefore an object of this invention to provide a printing transfer arrangement using a transfer band and means for transferring the image on said band onto a record sheet.

Another object of this invention is to utilize inertial, capillary and surface bonding forces as means for transfer of the image from the band onto a record surface.

A further object of this invention is to'provide a transfer means for transferring an image from a continuously moving transfer band onto a record sheet in a manner capable of being utilized in the above-identified cross-references.

According to the broader aspects of the invention there is provided a means for transferring an image from a transfer band ontoa record sheet, including means for accelerating said band toward said sheet, and means on said band to cause rapid deceleration of said band, whereby corresponding forces are utilized for transfer of said image onto said sheet.

A feature of this invention is to provide the transfer of the images by purely inertial means.

Another feature of this invention is to provide the transfer of the images by kissing contact, wherein for short periods of time the character image is in contact with both the transfer band and the record sheet.

Still another feature of this invention is to utilize a combination of both inertial transfer and kissing contact to effect the transfer of the character image from the transfer band to the record sheet.

BRIEF DESCRIPTION OF THE DRAWINGS The following description will be more clearly understood if reference is made to the accompanying drawings in which:

FIG. 1 illustrates the printing apparatus and transfer means according to the invention;

FIG. 2 is a side view taken along line 22 of FIG. I', and

FIGS. 3A through 3C illustrate the types of transfer to be described herein.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring first to FIG. 1, a transfer band 11 carrying a character image 12 is moved steadily around by pulleys 13 past a character forming station 14 and around to a record sheet 15 onto which the image 12 is to be transferred. At some point in a print cycle, the character image 12 formed on the moving band is adjacent to a specific location on record sheet 15. When this coincident occurs, a transfer of the image is caused to take place.

The following description will consider primarily liquid inks, however, the procedures to be outlined apply equally to dry inks that can be made to selectively adhere to the surfaces through controlled magnetic, electrostatic or molecular forces, or by a controlled liquefaction and accompanying capillary forces.

Referring additionally to FIG. 2, the transfer of the ink image droplets 21 is brought about by means of a power pulse generator 16 which is connected to an electromagnet 17 which, when activated, interacts with armature 18, biased in the open condition by spring 19, so as to cause the transfer band 11 to be rapidly moved toward the record sheet 15. Just as the band 11 approaches the sheet 15, its inward movement is abruptly stopped as the band ribs 20, as more clearly shown in the FIG. 3A,'strike the solidly backed paper 15. A rapid deceleration is thus produced resulting in corresponding inertial forces which are sufficient to detach the ink droplets 2] and cause them to fly onto the paper, this is shown in FIG. 3A below the center line. Above the center line of FIG. 3A are the droplets 21 just before the moment of impact. This transfer technique may be termed pure inertial transfer. a

A further advancement of this transfer arrangement just described involves what may be termed transfer by kissing contact. Here the physical mechanism is similar to the pure inertial method described but with one important difference. The distinction, as may clearly be seen in FIG. 3B, is that in kissing transfer the band I1 is allowed to be moved close enough to the paper 15, at the instant of transfer, so that the droplets 21 actually touch the paper 15 while still attached to the band 11. As in the inertial approach, the spacing ribs 20 are used to prevent the major band surface 11 from hitting the paper. However, in kissing transfer, the rib height 20 approximates the ink droplet height (typically .002 inch to .005 inch rather than being of a substantially greater distance as in the case of pure inertial transfer. This is illustrated by the difference in rib height 20 between FIG. 3A and 38. Also, notice that there isn't any difference before or after impact as was the case in FIG. 3A.

A key factor in successful kissing contact transfer is to assure short periods of time during which the ink mass is in contact with both the paper and the band. This requirement is easily met in practice by keeping the actuating electrical pulses, from a generator 16, shorter that the time needed for the armature 3 to move the distance to the paper. Additionally, the elastic properties of the system, including spring 19, cause the moving element to bounce away from the sheet rapidly, thereby minimizing the contact time.

Another aspect of this invention recognizes that the ink droplets 21 can be significantly deformed by inertial forces which, are not large enough to cause complete removal, but are sufficient to elongate the drops themselves. The upper portion of FIG. 3C shows the droplets prior to contact on the sheet 15. and the decelerating force at the time of contact is shown in the lower portion of FIG. 3C. The inertial effect, as can easily be seen in the drawing, causes the droplets 21 at the time of contact to become elongated. When this decelerating force occurs, they stretch in the direction of the sheet 15. The mechanism of ink droplets moving from the band to the paper involves both the movement of the band, as an inertial transfer, and the distortion of the droplets 21. The distortion is effected by rapid deceleration caused when ribs 20, which are not as high above the droplets as in FIG. 3A and are not substantially equal to the droplet height as in FIG. 3B, but are at some intermediate height as shown in FIG. 3C, this allows the distortion of the droplets and the transfer of the droplets from the band face to the record sheet.

The means shown for moving the band toward the paper is only one of many possible ways of meeting the requirement.

Another approach which will be recognized by one skilled in the art is to use the electrohammer" principle where a rapidly changing high intensity magnetic field is employed to simultaneously induce currents in and attract a nonferrous conductive armature. Still another means is to use a motor drive to set a spring capable of providing the necessary forcedistance relationship. Then by mechanically triggering this spring, an actuating bar is propelled toward the paper with a velocity needed for transfer.

In summary, it can be noted that there is described therein two basic transfer techniques, the pure inertial technique and the kissing contact technique. With these two basic techniques is described a third combination technique which employs both the inertial technique and the kissing contact technique, wherein the ink movement from the hand to the paper involves both the movement of the band and distortion of the droplets. While the preceding description has primarily considered liquid ink droplets, the concepts outlined may be applied equally to dry inks that can be made to selectively adhere to paper and band surfaces through magnetic, electrostatic, or molecular forces or by controlled liquefaction and accompanying capillary forces.

While I have described above the principles of my invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention as set forth in the objects and features thereof and in the accompanying claims.

lclaim:

1. Printing apparatus comprising:

a transfer band having rib members extending from its face surface, said ribs and said face surface together forming a U shaped member;

a character forming station for forming an ink image on said face surface of said band;

a transfer station including a record sheet for receiving said image;

said ribs normally facing and being spaced from said record sheet;

means for accelerating said band toward said sheet to impact said ribs on said sheet including an armature located on the side of said band opposite said face surface, and an electromagnet located opposite said rib members and be hind said record sheet onto which the image is to be transferrcd; and

said armature, upon impulse of said electromagnet, moving said transfer band rapidly toward said sheet. to impact said rib members on said record sheet and thereby effect rapid deceleration of said band and the transfer by inertia ofsaid image onto said sheet.

2. Apparatus according to claim I wherein said rib members are substantially the same height as the image on the face of said hand.

3. Apparatus according to claim I wherein said rib members are higher than the image on said band so that when said rib members impact said sheet, the decelerating force produced causes inertial transfer of the image from the band surface onto the sheet.

4. Apparatus according to claim 3 including spring bias means attached to said armature for causing said armature to rapidly rebound, thereby minimizing the contact time between said rib members and said record sheet.

5. Apparatus according to claim 4 wherein said image is formed by a plurality of ink droplets adhering to the face of said band and having a droplet height ofapproximately .002 to .005 inch. 

